Contactless tachometer using arduino

Contactless Tachometer using arduino

Contactless Tachometer using Arduino Uno with codes.

Tachometer is a device used for measuring the number of revolutions of an object in a given interval of time. Usually, it is expressed in revolutions per minute or RPM. Earlier tachometers purely mechanical where the revolution is transferred to the tachometer through a mechanical coupling (cable or shaft), the rpm is determined using a gear mechanism and it is displayed on a dial. With the advent of modern electronics, the tachometers have changed a lot. This article is about a contactless digital tachometer using Arduino.The speed of the motor can be also controlled using the same circuit. The RPM and all the other informations are displayed on a 16×2 LCD screen.

Principle Behind the Circuit:

The basic principle involves a simple embedded system with a sensor.

a controller and an actuator. The sensor used here is the one consisting of a white LED and a phototransistor, the controller used is the microcontroller loaded with a compiled code and the actuator is a display device, displaying the speed of the motor. The sensor senses the speed of the motor without actually being in contact with it by the principle of white light transmission and reflection and generates a signal. This signal is converted into an electric signal and fed to the microcontroller, which is programmed to calculate the speed in terms of number of motor revolutions in one minute. This speed is displayed on the LCD.

components you need-

Arduino Uno

a pair of ir Rx and Tx leds or you can buy modules of ir sensor

some jumper wire

Contactless Tachometer Circuit:

A tachometer is basically used to measure angular speed of a motor. It can be the mechanical device with a warm gear and spindle arrangement or an electrical device which converts the angular speed into electrical signal. The electrical tachometer, in turn, can be an AC tachometer or a DC tachometer. While a conventional tachometer is a contact tachometer which can produce erroneous results due to change in contact parameters, a digital tachometer is preferred which doesn’t require any contact with the device whose speed is to be measured. It basically works on the principle of retro-reflective scanning, wherein a light source device like LED transmits light signal to the retro reflective target device which reflects the light, which is in turn received by the light detector.